1. Field of the Invention
The subject invention generally pertains to ventilation systems and more specifically to an emergency system for counteracting biological or chemical contamination of the air inside of a building.
2. Description of Related Art
At times, the breathable air within a building can become contaminated with biological or chemical toxins. This can occur naturally within a building's conventional HVAC system (heating, ventilating, and air conditioning system), or can be caused intentionally by terrorists and others employing chemical or biological warfare. Since the source of contamination can exist and even originate in the building's existing ductwork, using the ductwork may be ineffective and even detrimental in attempting to clear the air.
However, providing a second ventilation system of ductwork that is designated specifically for such emergencies can be expensive and difficult to retrofit in existing buildings. Moreover, such an emergency ductwork system may also be subject to contamination as well.
Some emergency ventilation systems, as disclosed in U.S. Pat. Nos. 4,380,187 and 5,720,659, use a building's existing bathroom plumbing to provide breathable air therethrough in the event of a fire. Such a system provides an enclosed bathroom as a small, temporary sanctuary from smoke. This may be inadequate, however, in large, heavily populated buildings where there may only be a few bathrooms, such as, for example, an airport terminal, government building, or school. Moreover, smoke has an odor and can be seen, thus people can respond accordingly. Many chemical and biological toxins, on the other hand, are odorless and invisible, so it may be difficult to quickly alert everyone of the danger and the appropriate action to take.